1. Field of the Invention
This invention relates generally to protective coatings and, more specifically, to an aqueous based, strippable coating which forms a temporary, protective layer on a variety of substrates including metal, glass, concrete, natural and synthetic elastomers and various other porous, non-porous and painted substrates and which is easily peeled or washed from the substrate.
2. Description of the Prior Art
A demand exists at the present time for a coating composition suitable for the temporary protection of the surface of an article through the deposition on the surface of a coating which can subsequently be easily removed. For example, in the case of painted or polished metal manufactured articles, such as automobiles, a need exists for such a coating composition to protect the automobile against weathering, contamination from the atmosphere, chemical attack or accidental damage during handling, storage and transit. Preferably, the coating composition is easily removed later without deleterious effect upon the surface in question. Such a composition would be especially advantageous in the case of automobiles, where a newly completed vehicle may have to be stored out of doors for a period of time and then be driven or transported to another location. The effects of sunlight, atmospheric contamination and weathering can result in a significant loss of retail value of a vehicle which has never left the dealer's lot.
One early attempt to remedy this problem was the use of a wax coating on the automobile body. Wax provides a weatherproof and, to some extent, damage-resistant layer. However, the application of wax can be time consuming and difficult and its removal typically requires the use of an organic solvent.
Environmental, health and safety concerns have emphasized the need for a water based, strippable coating which forms a temporary protective layer on a variety of substrates, yet which is quickly and easily removed without the use of organic solvents. Ideally, such a coating composition is compatible with increasing government restrictions imposed on the user on the amounts and types of organic volatiles permitted to escape to the atmosphere.
A need also exists in the construction area for a temporary, strippable coating which is easily applied and easily removed. For instance, new windows need to be protected prior and during installation. Prior art attempts to provide a solution have included such substances as vegetable shortening and peanut oil. However, in many cases, the coating composition was more difficult to remove than the paint, mortar, texture, or other substance that may have splashed, dropped or otherwise deposited onto the window surface.
It is an object of the present invention to provide an aqueous based, strippable coating composition capable of providing temporary protection to a target substrate and yet having the desired release characteristics for facilitating cleanup operations.
Another object of the present invention is to provide such a coating composition which is mechanically peelable or strippable as well as being water strippable.
Another object of the invention is to provide an aqueous based, strippable coating composition which is more environmentally acceptable than are the currently available strippable coatings.
The strippable coating composition of the invention comprises a unique blend of non-volatile, film forming components which are dispersed in an aqueous base containing selected volatile components. Evaporation of the volatile components results in the deposition of a clear, temporary protective coating for temporarily protecting various substrates against damage from environmental effects. The coating is quickly and easily released from the substrate by peeling or washing off with water. The strippable coating composition can conveniently comprise:
a blend of non-volatile components comprising about 41-71% by weight of the coating composition, including:
about 34-54% by weight resin component; PA1 about 7-15% by weight release aids; PA1 about 0.1-0.6% by weight wetting aids; PA1 about 0.1-0.6% by weight defoamer; PA1 about 0.1-0.8% by weight dispersing aids; and PA1 about 1-5% by weight thickeners; PA1 about 0.1-2.5% by weight plasticizers and coalescents; and PA1 about 28.9-56.5% by weight water. PA1 about 34-54% by weight resin component; PA1 about 7-15% by weight release aids; PA1 about 0.1-0.6% by weight wetting aids; PA1 about 0.1-0.6% by weight defoamer; PA1 about 0.1-0.8% by weight dispersing aids; and PA1 about 1-5% by weight thickeners; PA1 about 0.1-2.5% by weight plasticizers and coalescents; and PA1 about 28.9-56.5% by weight water.
the strippable coating composition also comprising about 29-59% by weight of the coating composition of volatile components, including:
Additional objects, features and advantages will be apparent in the written description which follows.